In Japan, intense instruction in maths and the Japanese language begins at the age of six and continues to at least 15. Photograph: Toshiyuki Aizawa/Reuters

Japan's state education system is often criticised for quashing original thought among pupils in favour of rote learning, and for placing an emphasis on theory rather than practical skills, especially when it comes to English. But it is this traditional approach that has helped Japanese pupils easily outperform their counterparts in England and Northern Ireland.

Formal, intense instruction in maths and the Japanese language begins at the age of six and continues through to 15, the earliest age at which pupils can leave school. Those who elect to go on to senior high school – the rough equivalent of an English sixth form college and a traditional route to higher education – through to age 18 must study an eclectic range of subjects, including maths, Japanese literature and English.

Japanese senior high school teachers, and their pupils, are often incredulous when they learn that 16- to 18-year-olds in England can drop maths and literature and study just three A-level subjects of their choice. Japan's approach – rote learning accompanied by regular reviewing and testing – has proved hugely successful in establishing basic academic skills among pupils. The country's literacy rate is frequently put at 99%.

According to guidelines introduced by the education ministry, Japanese children should have learned how to read 1,006 kanji – Chinese characters used in the modern Japanese writing system – by the time they leave primary school, and a further 1,130 characters by the time they end their compulsory education at the age of 15.

Those who continue to senior high school are expected to be able to write all 2,000-plus characters – considered the minimum requirement to function in Japanese society.

Japanese children are thought to develop a working knowledge of basic mathematical patterns early on, thanks to the use in primary school classrooms of the soroban, a type of abacus based on the Chinese suanpan. Most young children in Japan own a soroban, and it is not unusual for older shopkeepers, schooled in the art of the abacus before the spread of electronic calculators, to use one to tot up bills.

Japan's approach to academic basics has its drawbacks, however. Even well-educated adults display poor communication skills in English, despite having studied the language as an exam subject for six years at junior and senior high school. At the same time, though, many pupils leave school with a good working knowledge of English grammar and decent comprehension skills.

The stress on memorising information and passing exams, which begins in primary school and continues through to senior high, has been blamed for stifling critical, independent thought and placing too much pressure to succeed on children as young as five.

Japan, like South Korea – which performed well in OECD numeracy tests among 16- to 14-year-olds – is home to a huge number of cram schools, called juku. There, children of all ages spend their evenings receiving extra tuition in the hope of edging ahead of their peers in the race for a place at a prestigious university.